The present disclosure relates generally to electromagnetic devices and more particularly to an electromagnetic device having discrete wires.
It is well known for an electric motor to have a stator including stacked sheets or laminated metal rings with poles or teeth inwardly projecting therefrom. Inductive wires are commonly wound around a middle of each pole. Examples of such stators are disclosed in U.S. Pat. No. 7,567,009 entitled “Stator Arrangement for an Electric Machine and a Method for Manufacturing the Stator Arrangement” which issued to Gu on Jul. 28, 2009, U.S. Pat. No. 5,194,775 entitled “Electric Motor Stator Tabs” which issued to Cooper on Mar. 16, 1993, and PCT Patent Publication No. WO 2012/118797 entitled “Rotor Apparatus” which published to Müller et al. on Sep. 7, 2012; all of which are incorporated by reference herein. These prior stator and pole designs, however, can be prohibitively expensive to manufacture for low volume production and prototype batches. Furthermore, the conventional Gu and Cooper constructions can also be disadvantageously subject to corrosion damage.
Another electric motor construction is disclosed in U.S. Pat. No. 8,253,299 entitled “Wound Magnetic Flux Channel Transverse Wound Stator Permanent Magnet Motor” which issued to Rittenhouse on Aug. 28, 2012, which is incorporated by reference herein. This arrangement employs coil windings between teeth protruding from a stator rim. The stator rim is an injection molded polymeric part against which a transverse coil winding is also attached. This device, however, will not create the tailored pole shapes desired with the discrete wires of the present invention, and it still requires a separate and preformed stator rim and pole unit with its associated expensive molds and tooling.
In accordance with the present invention, an electromagnetic device includes discrete wires for its poles or teeth. In another aspect, an electromagnetic device includes a stator unit and an adjacent movable unit, at least one of which includes magnetic flux-carrying poles, with a majority of each pole including multiple discrete wires. In another aspect, the movable unit is an electric motor rotor, a linear electric motor armature, a solenoid armature, or an electric generator rotor. A further aspect provides an electromagnetic device having a generally T-shaped tooth with discrete wires extending along a middle throat or leg of the tooth and also within a crossing section of the tooth. In yet another aspect of the electromagnetic device, a stator, rotor and/or armature includes multiple discrete and flux-conducting wires with permanent magnets attached to or closely adjacent to a periphery of at least some of the discrete wires.
The present electromagnetic device is advantageous over conventional constructions. For example, the present device is less expensive to manufacture and requires less capital tooling especially for low production and prototype volumes. Furthermore, the present device advantageously deters corrosion of the stator, rotor and/or armature by encapsulating the discrete wires within a binder, either through a pre-assembly coating, post-assembly molding, vacuum pressure impregnation, spraying or the like. Moreover, the present device can weigh less than traditional devices and the discrete wires also provide load-bearing structural elements, both of which are especially advantageous to counter destructive inertial and/or centrifugal forces acting on a rotating rotor. The present electromagnetic device also advantageously allows for specially customized and tailored shapes for each tooth with minimal tooling expenses. Additional advantages and features of the present invention will become apparent from the following description and appended claims taken in conjunction with the accompanying drawings.